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Published on: November 21, 2012
Prior exposure to methylenedioxyamphetamine (MDA) induces serotonergic loss and changes in spontaneous exploratory
A Harkin1, T J Connor, J Mulrooney
1Department of Pharmacology, National University of Ireland, Galway. andrew.harkin@nuigalway.ie
Abstract:
The substituted amphetamine 3,4 methylenedioxyamphetamine (MDA) is a popular recreational drug of abuse. Administration of MDA to experimental animals has been shown to induce damage to serotonergic axons and nerve terminals. However, there is a lack of information on whether these treatments can produce any long-term changes in behavioural performance particularly under stressful conditions. In the present study, MDA (7.5 mg/kg; i.p.) was administered twice daily to adult male Sprague Dawley rats for four days. Four weeks following the last dose, spontaneous behaviors of these animals were tracked and scored in a novel "open field" environment using an automated video registration and computer interpretation system. Changes in behavior were observed in MDA treated animals including reductions in exploratory oriented behaviors (locomotion and rearing) and increases in grooming behavior when compared to vehicle treated controls. MDA-treated animals also displayed an enhanced locomotor and stereotyped response to d-amphetamine (12 mg/kg; i.p.). Significant reductions in 5-HT concentrations (20-30%) were observed in the frontal cortex, amygdala, striatum, and hypothalamus as a result of MDA treatment. In addition, [3H] paroxetine binding was reduced by (40%) in the cortex of MDA treated rats indicating that the decrease in 5-HT concentrations were accompanied by a reduction in intact presynaptic 5-HT nerve terminals. Changes in behavioural performance in a novel "open field" environment and following d-amphetamine challenge might be considered as a behavioural model of serotonergic deficit induced by MDA. The findings of this study also suggest that MDA use may increase both the abuse potential, and the propensity to develop psychosis as a result of abusing other psychostimulants such as d-amphetamine.
Insights
3,4-methylenedioxymethamphetamine (MDA) causes long-term behavioral changes and serotonin deficits in rats. MDA-treated rats showed altered open field behavior and increased sensitivity to d-amphetamine, suggesting potential for increased abuse and psychosis risk.
Area of Science:
- Neuroscience
- Psychopharmacology
- Behavioral Science
Background:
- 3,4-methylenedioxymethamphetamine (MDA) is a recreational drug known to damage serotonergic systems.
- Long-term behavioral effects of MDA, especially under stress, remain under-investigated.
Purpose of the Study:
- To investigate long-term behavioral changes and neurochemical alterations following MDA administration in rats.
- To assess the impact of MDA on behavioral responses to a psychostimulant challenge.
Main Methods:
- Adult male Sprague Dawley rats received MDA (7.5 mg/kg) twice daily for four days.
- Spontaneous behaviors were assessed in an open field test four weeks post-treatment.
- Serotonin (5-HT) concentrations and [3H] paroxetine binding were measured in brain regions.
Main Results:
- MDA-treated rats exhibited reduced exploratory behaviors and increased grooming in the open field.
- MDA-treated rats showed enhanced locomotor and stereotyped responses to d-amphetamine.
- Significant reductions in 5-HT levels (20-30%) and [3H] paroxetine binding (40%) were observed in multiple brain regions.
Conclusions:
- MDA administration induces lasting behavioral deficits and serotonergic neurotoxicity in rats.
- These findings suggest MDA may increase the risk of psychosis and stimulant abuse.
- The observed behavioral changes may serve as a model for MDA-induced serotonergic deficits.
